The present invention relates to a scaffold, particularly a scaffold for construction work, which comprises a plurality of vertical posts and a plurality of horizontal and diagonal locking bars connected to each other.
In convential scaffolds for construction work a number of collars or flanges are rigidly arranged on each vertical post, which flanges are vertically spaced from each other. Each flange has a peripheral portion extended outwardly radially from the vertical post and protruding upwardly from the bottom of the flange. The ends of the horizontal and diagonal locking bars are provided with pawls which in assembly engage with the peripheral edges of the respective flanges. The advantage of these known in practice scaffold arrangements is that the pawls provided on the ends of the horizontal and diagonal locking bars can be brought from above into engagement with the rigidly supported vertical posts so that the pawls seize the respective edges of the flanges mounted to the posts. There is also no space required for displacement of the horizontal and diagonal locking bars along the direction of elongation of the respective bars.
A further advantage of these known scaffold constructions resides in that the joint points on the vertical post, which are formed by the flanges surrounding the vertical post and rigidly connected thereto to form the locks provide, after the wedges have been inserted into the respective pawls, very rigid connections and therefore a very rigid and stable scaffold structure as a whole.
In practice, since a great number of vertical posts as well as horizontal and diagonal bars are utilized in one scaffold, it is rather difficult to determine which wedges are tightly inserted into the respective holes formed in the pawls and which wedges are loosely mounted in the holes of the pawls; therefore an operator can not see whether each wedge is rigidly hammered into the pawl of the locking bar or it is loose. It can happen during the assembly of the scaffold that the wedge which was in the beginning tightly hammered in the hole of the pawl will then loosen, which would lead to a play in the connection. The disadvantage of these scaffold assemblies is that any pawl of the locking bar could be inadvertently lifted away from the flange on the vertical post and the locking bar could be therefore detached from the vertical post, which is dangerous.
There have been suggested constructions of pawls which do not employ a wedge connection and which should, however, provide a lock against an inadvertent detachment of the pawl from the flange of the vertical post and prevent loosening of the locking bar from the vertical post; these arrangements, however failed to provide rigid joint points whereby a considerable movement play in the region of the connection between the vertical post and the horizontal locking bars has been possible when the scaffold was in an operative position.